Rheostat.



H. A. STEEN.

RHEOSTAT.

APPLICATION FILED AUG. 1, 1910.

1,016,793. Patented Feb. 6, 1912.

sistance.

UNITED STATES PAT T; orFIoE.

mrnAn A. srnnn, or MILWAUKEE, WISCONSIN, Assrononir Y comm, A CORPORATION or NEW mnsnr.

nnnosrAr.

Specification of Letters Patent.

I 'I.Is-,

Application filed August 1, 1910. Serial No. 575,028,

To all whom a y mm.- Be it known that I, HALFDAN A. STEEN,

va subject of King of Norway, residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented certain new and useful Improvements in Rheost-ats, of which the following exact specification.

tion of current is often required, and insome cases it is necessary that the increase or decrease of current be continuous, that is, unspasmodic. With the ordinary rheostat a fairly close regulation of current may be obtained by dividing ,the resistance into a great number .of steps, but this construction is expensive and there is a marked lncrease or decrease of current at each step? t The object of my invention is to provide an ordinary rheostat having a resistance divided into a small number of steps with an arrangement which will make possible a close and continuous adjustment of the re- With this object in view I provide a main variable resistance and an auxiliary resistancc, and means for interconnecting and varyin said resistances in such a way that the a ustment 1s continuou's. The auxiliary resistance is preferably'a compressible reslstance, although for some features of my invention this is not essential.

The various novel features of my inven tion will appear from the description and drawings, and will be particularly pointed out in the claims. I

Figure 1 is an elevation of a rheostat em. bodymg my invention, parts being shown in section for the sake of clearness; and Figs. 2, 3, 4, and 5 are diagrammatic views of my rheostat showing connections in different positions.

A main resistance 10, a compressible resistance, such as a carbon pile 11, and the parts cooperating with said resistancesare mounted upon an insulatin base 14. The main resistance 10 is divided into a number of sections by contacts 12, 12 12", and 12 arranged in a circular row, and these sections may be cut into or out of circuit by the movement of an arm 13 carrying a brush 13.

is a full, clear, and;

The carbon pile ll consists of a number of carbon disks 15, which are preferably inclosed in, but insulated by insulation 15 from a metal tube 16 havlng a number of circular cooling flanges 17. The ends of this tube 16 are closed and supported by caps 18 and 20, secured to the base 14. An adjusting screw 19 passes through the cap 18 and varies the position of the upper end of the pile 11,while alunger 21 passes through the cap 20 and ears against the lower end disk of such pile. One end of the plunger 21 is'connected to a toggle 22, at the knee of'which is a roller 22 which rides on the periphery of a cam 23. The cam 23 Patente'd Feb. 6,1912. I

is secured to a shaft 24 and-is rotated by any suitable means, such as an operating handle 25.

Secured to the movable arm 13 and insulated therefrom by insulation '13 is a brid ing member 26, having one brush 26 whit l brush 26 which engages a curved bar-27. One end of the carbon pile '11 is electrically connected to the bar 27, and the other end to the arm 13. The space between successive contacts 12 is greater than the width of either brush 13* or 26, so that neither of said brushes will ever bridge two. of the contacts-- v The arm 13 is moved intermittently by any suitable device, which consists of a driving portion mounted upon the shaft 24 and a driven portion secured to the arm 13. The driving portion comprises a pin or tooth 28.and circular segment 29, and the driven portion a (air--- cular segment 30 having a number of notches 31 and concave portions 32. When the shaft 24 is rotated, the pin 28 at each rotatlon engages one of the notches 31 and engages the contacts 12 and anothersuch as a Geneva gear,

moves the arm 13 one step forward or back.

When the pin 28 is out of engagement with the notches 31 the circular segment 29 engages one of the concave portions 32 and locks the arm 13.

In Fig. 1, the rheostat is shown in its ofi' posltlon. In this position the carbon pile 11 ,is released and the brushes 13 and -26 areout of engagement with the resistance contacts. If the operating handle 25 is rotated .in a counter-clockwise direction, the pin 28,

which is in engagement with one of the notches 31 of the member 30 moves the arm 13 m a clockwise direction until it assumes further rotary movement.

the position shown in Fig. 2.. This puts the carbon pile 11,which has not yet been compressed, in series with the main resistance 10, and the total resistance of the rheostat is at its maximum. After the arm 13 has been moved to the position shown in Fi 2,further counter-clockwise movement 0 the bandle disengages the pin 28 from the notch 31, and brings the circular segment 29 into eng'ggement with the concave portion 32 to 100 the arm 13 for the time being against Also, acting through the cam 23 and the toggle 22 the continued movement of the handle 25 gradually compresses the carbon pile 11 to decrease its resistance, until when the maximum pressure on the carbon pile isapplied, the pin 28 has engaged the next notch in the member and has thereby moved the arm 13 to the position shown 1n Fig. 3. When the arm 13 assumes the position shown in whereupon the Fig. 3, the brushes 13' and 26'! both engage the contact 12", short-circuiting the carbon pile and allowin the current to pass along the arm 13. and t roughthe whole of the re sistance 10. The pin 28 being still in engagement with the member 30, a continuation of the movement of the operating handle in a counter-clockwise direction brings the arm 13 into the position shown in Fig. 4, pin leaves the notch in the member 30 and t e segment 29 looks the arm for an interval against further movement. During the early part of this last movement, and before the brush 26 engages the contact 12 the carbon pile is released, due to roller 22 engaging the hollow part of the cam to bring it to its maximum resistance value. In the position shown in Fig. 4 the brush 26 is engaging contact 12", and brush 13 is engaging contact12, the carbon pile 11 therey being connected in parallel with the first section of the resistancelO, causing the total effective resistance of the rheostat to be gradually and unspasmodically decreased. If a cycle the same as that used in'passing between the positions shown in Figs. 2 and 4 is now repeated, the first section of the resistance 10 will be cut out of circuit, causing another gradual decrease in the efiective rheostat resistance. The carbon pile 11 will first be gradually compressed, thus reducing its resistance and shunting more and more current around the first section of the resistance 10 until, when the pile has been compressed to its maximum, such section is practically short-circuited. The arm 13 is moved to the position shown in Fig. 5, in which position the brushes 13 and 26" both engage the contact 12 to short-circuit the carbon pile. The first section of the resistance 10 is now out out of circuit. By continuing the movementof the operating handle in a counter-clockwise direction, the carbon pile will be first released, and then connected in parallel with the next section of resistance, then 00m pressed to shunt current away from such section, and then short-circu'ited. This may be repeated for each section of the resistance.

.The operating handle may be stopped at any desired point leaving any desired amount of j cuit is thereby continuously or unspasmodically varied. For cutting resistance into circuit, the operatin the clockwise direction, produc' results just the reverse of those described a ove.

I have described my invention in what I now consider to be the preferred form, but many modifications may be made in the precise arrangement shown and described and all such which do not involve a departure from the spirit and scope of my invention I aim to cover in the following claims.

What I claim as new is:

1. In a circuit-controlling device, the combination of a'main resistance, a compressible auxiliary resistance, means for connecting said compressible resistance in parallel with portions of said main resistance, and means for compressing said compressible resistance.

2. In a circuit-controlling device, the combination of a main resistance, means for cutting into or out of circuit cuit portions of said main resistance.

4. In a circuit-controlling device, the combination of a circular rowof contacts, resistance sections connected between successive pairs of said contacts, two brushes for successively engaging said contacts, said brushes being insulated from each other, a compressible resistance connected between said brushes, a device for compressing said resistance, and means actuated by said device for operating said brushes.

5; In a circuit-controlling device, the combination of a main resistance, an auxiliary compressible resistance, means for intermittent y connecting portions of said main resistance in parallel with said compressible resistance and for varying said main resistance, and means for intermittently compressing said compressible resistance and operating the aforesaid means.

6. In a circuit-controlling device, the combination of a main resistance, a continuously handle is rotated in variable auxiliary resistance, and means associated with said main resistance for connecting said auxiliary resistance in parallel with a section of said main resistance and for varying said auxiliary resistance.

7 In a circuit-controlling device, the combination of a main resistance, a continuously variable auxiliary resistance, a movable member for varying said main resistance and for connecting portions of said main resistance in parallel with said auxiliary resistance, a device for varying said auxiliary resistance, and means interlocking with said device for operating said movable member.

8. In a circuit-contr0lling device, the combination of a main resistance, and means including a pressure varying member for establishing a shunt circuit around a portion of said resistance and continuously varying the resistance of said shunt-circuit.

9. In a circuit-controlling device, the combination of a main sectional resistance, an auxiliary compressible resistance, means for connecting said auxiliary compressible resistance in series with a variable amount of said main resistance, and means for varying the compression of said compressible resistance.

10. In a circi1it-controlling device, the combination of a main resistance, a variable auxiliary resistance, means for cutting into or out of circuit portions of said main resistance and for connecting said auxiliary resistance in parallel with fportions of said main resistance, and means or regularly and intermittently operating said first mentioned means.

11. In a circuitcontrolling device, the combination of a main resistance, a variable auxiliary resistance, means for cutting into or out of circuit portions of said main resistance, and for, connecting said auxiliary resistance in parallel with portions of said main resistance, and also for intermittently short circuiting said auxiliary resistance.

12. In combination, a main sectional resistance, and means including acam operated member for establishing a single-path shunt circuit around a portion of such resistance and for varying the resistance of such shunt circuit.

13. In combination, a main resistance, an auxiliary resistance, and means during a single operation thereof for rendering in order said auxiliary resistance its maximum effective value, connecting it in parallel with the main resistance, and reducing said auxiliary resistance to its minimum effective value, and then short-circuiting, said auxiliary resistance.

In testimony whereof I affix my signature,

in the presence of two witnesses.

HALFDAN A. STEEN. Witnesses:

JOHN L. JoHNsoN,

CHAS. L. BYRON. 

